The invention relates to a compact video microscope according to the preamble of claim 1, as it is described in EP 380 904 A1,and/or according to the preamble of claim 2.
U.S. Pat. No. 4,206,966 has disclosed a microscope in which for the purpose of visual representation the object image is projected onto the rear side of a ground glass screen which is accommodated in the upper housing part of the microscope and serves as a viewing screen. Moreover, U.S. Pat. No. 5,031,099 has disclosed a computer-assisted video microscope which comprises a microscope with a conventional microscope stand, a computer arranged separately therefrom, and peripherals associated with the computer, such as monitor, printer, keyboard etc. In this case, the computer includes diverse plug-in cards which permit both communication with the peripherals and the driving of different motor functions of the microscopexe2x80x94such as the motorized focusing drive and the motorized mechanical stage.
The substantial space requirement is a disadvantage of such non-integrated solutions, because the individual componentsxe2x80x94such as monitor, computer and other peripheralsxe2x80x94are arranged next to one another on a working surface. Again, the many connecting cables required reduce the reliability of the overall design and constitute obstacles in the operating environment. The representation of high-resolution images has to date been associated with monitors having picture tubes with a large screen diagonal, because by contrast with flat screens the individual pixels are relatively large with picture tubes. Associated with this is not only a high space requirement, but also a high weight of the monitor, and this makes it difficult to use the overall system at changing locations. Likewise a hindrance to such use at changing locations is the need to disconnect cable connections during disassembly and to have to reestablish them during assembly.
The device described in WO 96/20421 A1 serves the purpose of observing a current microscopic image in common with a pictorial representation of a spatial object obtained by a second device. The known arrangement is characterized in that it includes an xe2x80x9cadaptive control devicexe2x80x9d which by automatically matching the two pictorial representations always offers the observer a geometrically consistent superimposed image. What is decisive here is that this xe2x80x9cadaptive control devicexe2x80x9d uses algorithms, position-measuring devices and positioning motors to relieve the user of the work of correctly setting in spatial and geometric terms the microscopic representation and that produced otherwise. Separate monitors are used for the representation, while small displays which are observed via the oculars of the microscope used provide an alternative.
By contrast, the video microscope or the video tube according to the invention permits the visual manual production of a superimposition of the current microscopic image and a storedxe2x80x94preferably microscopicxe2x80x94image in apparently one plane directly on the integrated flat screen.
DE 196 09 288 A1 describes a video microscope which is installed in the form of a miniaturized module in a commercially available computer and is typically accommodated in a drive bay of said computer, or is operated as an external unit in a commercially available peripheral housing for computers. With its automated feed of standard specimen slides, this miniaturized microscope is suitable chiefly for routine tasks in medical laboratories. It represents, as it were, a counterpart to the present application, because in DE 196 09 288 A1 the microscope is installed in an existing computer, while the video tube according to the invention either contains the computer or is operated with a separate computer.
The quantitative optical microscope described in EP 380 904 A1 aims at creating a very high-resolution optical microscope for quantitative imaging using large sensor surfaces and high-aperture objectives for producing very large (xe2x80x9cultrawidexe2x80x9d) visual fields. The central aim of this optical arrangement is direct imaging of the object onto an image sensor while omitting any further imaging optical elements between the objective and image sensor. A high image resolution is to be achieved both by a large visual field in conjunction with a high numerical aperture of the objective, and by a large-area image sensor provided with many pixels. It is to be rendered possible thereby to use a single image to obtain a good overview, and also to study details at any desired point by observing a subsequently determined section. This known proposed solution would require the creation and provision of such special objectives. The commercially available objectives quoted in the description do not deliver this type of imaging by themselves, since they require either additional compensating optical systems, or else a tubular lens in order to meet the demands of adequate optical correction, and/or to generate at all a real optical intermediate image. However, it is precisely these additional optical systems which the invention aims to exclude. Furthermore, the use of a video signal for transmitting image data between the image sensor and computer is expressly excluded. Again, aspects of an integration of all the components into a single housing, and the exclusive observation via a screen are neither addressed nor set forth.
A disadvantage in the principle of known proposed solutions is to be seen in that microscopic images for electronic image sensorsxe2x80x94such as CCD camerasxe2x80x94are generated by an imaging optical system which is connected to the same tube and the associated tubular lens which also generates the intermediate image for the oculars. In the case of the use of the nowadays generally customary objectives for optical microscopes, the optical system for the image sensor or sensors is always situated downstream of a tubular lens. However, because the diagonals of the active receiving surfaces of image sensors are much smaller than the relatively large intermediate images required for the oculars, in the designs nowadays customary the image enlarged by the tubular lens is subsequently reduced again for projecting onto the image sensors. This contradicts the basic requirement of generating an optical microscopic image using as few lenses as possible, in order to keep disturbing influencesxe2x80x94such as reflections and light absorption by the optical componentsxe2x80x94slight.
It is therefore the object of the present invention to create a video microscope or a video tube for microscope stands for all contrasting methods and types of specimen customary in optical microscopy which permits a compact design, a more comfortable way of observing the image and the data linked to it, as well as permitting operation which is supported to the greatest possible extent by suitable software.
This object is achieved by means of a video microscope having the features described herein, and by a video tube having the features described herein. Advantageous developments of said microscope or video tube are the subject matter described herein.
For such a microscope or for a video tube of such a type, the weight and the space requirement of the overall system are lastingly reduced. Finally, the purely light-optical observation of the image with the aid of tube and ocular(s) is dispensed with. Instead of this, it is rendered possible to orientate in the specimen by the optical representation of a survey image on the rear side of a flat screen. It is rendered possible to record, represent and document microscopic images in a purely electronic way without the assistance of film material or other image carriers of a chemical nature. By virtue of the fact that it is possible to install in the optical microscope components such as microphone, loudspeaker and miniature video cameras which are, for their part, linked to the installed computer via corresponding electronic signal transducers, further possibilities arise directly at the optical microscope from voice control of the optical microscope, the recording of voice data accompanying the image, and telecommunication including a video conference.
The video microscope according to the invention, or the video tube according to the invention has a closed housing inside which and on whose outer surfaces all the optical and electronic components are arranged for electronically recording and representing microscopic images of an optical microscope. For the purpose of recording microscopic images, the same housing contains electronic image sensors such as, for example, one or more two-dimensional or cellular CCD sensors with a sufficiently large number of pick-up elements, and the electronic components linked thereto, which serve the purpose of amplifying, influencing and digitizing the electric currents which originate from the image sensors and carry the image information. In addition, the same housing contains a computer and a flat screen for representing the microscopic images and data, along with operating surfaces which are generated by software in the computer. Components such as microphone, loudspeaker and miniature video camera can, in addition, be installed in the same housing.
In an alternative exemplary embodiment, the video microscope or the video tube is equipped for direct light-optical projection of images onto the rear side of the flat screen or a suitable projection surface in a plane which lies in or immediately downstream of the imaging plane of the flat screen, with the result that the projected light-optical image is visible to the observer inside the surface of the flat screen. It is possible there, given the use of the installed or another, remote computer for images to be observed together with characters, graphics and other images already generated electronically, without the assistance of oculars or similar optical systems. This device can be switched on quickly at any time in order to facilitate the search for specimens.
Optical inputs and outputs are present with both variants of the microscope or video tube according to the invention. Classical external components for optical microscopic methodsxe2x80x94such as co-observing devices together with normal tubes and oculars, photographic cameras, video cameras, image-reflecting units, drawing apparatuses and other known accessoriesxe2x80x94can be connected via said input and output. Said input and output can also be used in the known way to employ modules for confocal microscopy and laser devices.
Virtually all recent optical microscopes use the so-called infinite optical system, in which the objective initially unites the beams, which originate from objects out of the front focal plane, downstream of the objective with intersection points at an infinite distance. A tubular lens of suitable focal length generates the first intermediate image at a finite spacing, 160 to 250 mm being customary. Further lenses for adapting image sensors come into use downstream of said tubular lens, whose intersect distance is calculated for the generation of a relatively large intermediate image which can be employed for the use of oculars. Since the active surface of customary image sensors has much shorterxe2x80x94diagonals 4 to 12 mm being typical at presentxe2x80x94than the diameter, usual in the oculars, of the intermediate images (18 to 28 mm), the initially magnified images are subsequently substantially demagnified by adapter optical systems, which are complicated in part, for the purpose of adapting the visual field to the image sensors.
In the video microscope or video tube according to the invention, this situation is avoided in principle by virtue of the fact that no oculars are used for observing the images. The images are observed via the installed flat screen, using the unaided eye. This also eliminates the need to use a tubular lens with a long intercept distance, as is mandatory when using oculars. Instead of this, it is chosen to generate images for the image sensors more simply by contrast with the practice just described: the quasi-parallel light beams generated by the objective of the video microscope are focused directly onto the active surface of the image sensors, without the use of a tubular lens, by means of a zoom optical system of variable focal length but fixed image position. The use of such zoom objectives upstream of the image sensors permits the total magnification realized in the digital image, and thus also the size of the visual field on the object side to be conveniently adapted to the specimen situation. The change in the focal length can be supported via the installed computer and a motor controller connected to the zoom objective. Using suitable encoders, the respectively updated value of this additional image scale is recorded by the computer in a known way, displayed and taken into account in the digital image evaluation.
In addition, said optical system, which is driven by one or more motors and also by the computer, can also be used to undertake a correction to the image position as a function of the wavelength of the light employed, or of the focal deviation of the microscope objective used.